1. Field of Invention
The present invention relates to an acoustic unit for generating sound effect, and more particular to the acoustic unit incorporating with a loudspeaker or an acoustic module and its manufacturing method thereof, wherein the acoustic unit comprises a suspension to minimize a vibration thereof so as to enhance the audio quality produced by the acoustic unit, especially the audio at low frequency.
2. Description of Related Arts
A vibration system of a conventional loudspeaker generally includes a vibration plate, a voice coil, and a magnetic coil system. The voice coil is disposed in the magnetic coil system to magnetically induce with the magnetic coil system, a vibration of the vibration plate is thus produced and the vibration is controlled by a resilient suspension of the vibration plate, and thus an audio effect is produced by the loudspeaker. According to the conventional art, no matter the suspension is constructed to have a square shape or race-track like shape, when the vibration plate moves up and down at a relatively large vibration amplitude, a weight member at the center of the vibration plate will concurrently moves in an up-and-down direction and in a planar manner. As a result, the suspension will be easily deformed in response to the pulling and tearing force during the vibration. The problem is commonly found in the racetrack shaped suspension. Since the suspension is unable to move up and down in a balanced vertical manner, shaking of the vibration plate is thus inevitable. In other words, the sound produced by the vibration plate will not be clear.
The sound quality at the low-frequency is determined by the displacement and vibration frequency of the vibration plate. When a relatively large low-frequency audio signal is input, the vibration plate will moves up and down violently. At the largest displacement-position of the vibration plate, corners of the racetrack shaped suspension will be substantially pulled, such that the tearing force will be concentrated and exerted at the corners of the suspension. The mechanism can be better understood with the following description. When the racetrack shaped suspension is placed at a horizontal orientation and is pressed by a hand to cause the vibration plate to move downwardly, it can be viewed that the four corners of the suspension are the most seriously deformed locations to be pulled. In other word, the displacement of the entire vibration plate will be restricted by the four corners. Since the displacement of the vibration plate will be restricted at the corners of the suspension, and the desired low-frequency audio quality of the loudspeaker cannot be obtained. In addition, the displacement of the vibration plate must be increased if a better low-frequency audio quality is required. This means that the volume and size of the acoustic enclosure and/or loudspeaker should be relatively large enough, and thus it is not convenient for storage and transportation.